Entamoeba histolytica Antigen Detection

(contributed by William A. Petri, Jr.)

The "Entamoeba Test" (designed to detect but not differentiate the antigens of E. histolytica and E. dispar in stool specimens) and the "Entamoeba histolytica Test" (designed to detect specifically E. histolytica in stool) are available from the manufacturers (TechLab, Inc., Blacksburg, VA).

Briefly, the method is as follows: Assay microtiter wells are incubated with 0.1 ml of diluted specimen (stool diluted 1:1 in kit diluent) and 1 drop of mAb-enzyme conjugate for 2 hours at room temperature. The contents of the well strips are then shaken out, and washed 4 times in the wash solution. After washing, residual liquid is removed by striking the strip once against a paper towel, substrate solutions are added, and the strip incubated at room temperature for 10 min. Intensifier is then added and after an additional 10 min incubation the well strips are read in a microtiter plate reader (eg. Titertek Multiskan, Flow Laboratories, VA) at 450 nm. A positive result is defined as an optical density reading > 0.05 after subtraction of the negative control optical density. Sensitivity is calculated as true positive (TP)/TP + false negative (FN) and specificity as true negative (TN)/TN + false positive (FP).

Back to the Laboratory Methods Page

Back to the Entamoeba Homepage